This invention relates generally to flat panel displays in which an array of field emitters are selectively energized to emit electrons for impinging on a phosphor-coated transparent faceplate, and more particularly the invention is directed to improved field emission electrodes for use therein.
In the conventional flat panel display, the emission electrodes of the array of field emitters are generally conically shaped elements of molybdenum, silicon, or active material which readily emits electrons when exposed to high electric fields. It is considered important to form a sharp tip electrode in order to achieve electron emission at reasonable voltages of approximately 200 volts. A very high electric field can be formed at the tip with an anode voltage on the order of 200 volts. The electrons then strike a phosphor-coated face plate to form a display image.
Problems with this emitter design are numerous and give rise to short lifetimes and a high cost of production. Polycrystalline silicon emitters are frequently used because of ease of formation by physical vapor deposition through an aperture mask. However, the silicon material is rapidly eroded during use and is easily vaporized by electrical arcing to the anode.
The present invention is directed to an improved silicon emission electrode structure having increased life and ease of manufacture.